US1891622A

US1891622A - Screen printing machine

Info

Publication number: US1891622A
Application number: US502113A
Authority: US
Inventors: Flockhart James
Original assignee: Individual
Current assignee: Individual
Priority date: 1930-12-13
Filing date: 1930-12-13
Publication date: 1932-12-20
Anticipated expiration: 1949-12-20

Description

Dec. 20, 1932. J. FLQCKHART SCREEN PRINTING MACHINE Filed Dec. 15. 1930 6 Sheets-Sheet 1 Pic..

iNVENTOR:

JAMES FLOCKHART ATTORNEY Dec. 20, 1932. .1. FLOCKHART SCREEN PRINTING MACHINE Filed Dec. 15. 1950 6 Sheets-Sheet 2 NVENTOR:

JAM ES F LOCKHAR T BY I flaw 40% 1% ATTORNEY.

Dec. 20, 1932. T J. FLOCKHART 1,391,622

SCREEN PRINTING MACHINE Filed Dec. 13. 1930 6 Sheets-Sheet 3 FIG. 3.

INVENTORY JAMES FLOGKHART.

BY W

ATTORNEY J. FLOCKHART SCREEN PRINTING MACHINE 6 Sheets-Sheet 4 Filed Dec. 13. 1950 INVENTOR: JAMES FLOCK HART wam/45% ATTORNEY.

Dec. 20, 1932. I r J, FLQCKHART 1,891,622

SCREEN PRINTING MACHINE Filed Dec. 13. 1950 s Sheets-Sheet 5 INVENTOR: JAMES F LOCKHART.

ATTORNEY. v

D66. 20, J FLOCKHART SCREEN PRINTING MACHINE Filed Dec. 15.

1950 6 Sheets-Shet e 24 BNVENTOR:

JAMES F LOQKH A'L iT flag ATTORNEY.

Patented Dec. 20, 1932 UNITED STATES PATENT OFFICE JAMES FLOCKHABT, OI SAN FRANCISCO, CALIFORNIA SCREEN PRINTING MACHINE Application filed December 13, 1930. Serial No. 502,118.

that it is not limited to this form because it may be embodied in other forms. It is also to be understood that in and by the claims following the description it is desired cover the invention in whatsoever form it may be embodied.

For further particulars reference is here made to my copending ap iicatlons. as follows: fountain brush, Ser. 0. 396,082, filed Sept. 30, 1929; stencil frame, Ser. No. 396,083, filed Sept. 30, 1929; stencil printing machme, Ser. No. 429,387, filed Feb. 18, 1930; sheet gage, Ser. No. 436,502, filed Mar. 17, 1930; stencil printing apparatus, Ser. No. 438,504,

filed Mar. 24, 1930.

In the six sheets of drawings:

Fig. 1 is a side elevation of a screen printing machine constructed in accordance with this invention.

Fig. 2 is a plan view from above of the same.

Fig. 3'is a similar view of the power unit for actuating the same.

Figs. 4-5, taken together are an enlarged detail in side elevation of the power transmission means between the actuating cam Fig. 6 is a detail front view of the clutch Fig. 9 is a plan view from above of the same.

Fig. 10 is an enlarged fragmentary detail end view of one side of the ink fountain crosshead guide. 1

Fig. 11 is across section of the same. i

Fig. 12 is an enlarged detail view'in vertical section diagrammatically illustrating the ink fount in the open operative and spreading position.

Fig. 13 is a similar view of the samein' the closed, return, scraping position.

Fig. 14 is a plan view of the same combined with its guiding and operating assembly.

In detail the construction illustrated in the drawings referring to Fig. 1, comprises the main frame, preferably of cast iron, having two side members 11, suitably cross braced to form a substantial support for the operative mechanisms. The operating table or platen 2, extends across the top of the main frame at the front, and is securely bolted thereto. This platen may be composed of a the conventional laminated wood panel, to which paper registering guides may be thumb tacked, or it ma be of any other non-warping material suitab e for the purpose.

. The pillow bearings 3-3 are fixed onopposite sides of the top rails 44 of the mam frame. The eccentric blocks 5-5 are revolu ble in the bearings 3, and held in adjusted position by the set screws 6-6 respectively. The pivot shaft 7 has its opposite ends fixed in the blocks 55 so that it may be adjusted vertically with respect to the plane of the platen 2, by turning the eccentric blocks 55. The blocks are rotated by the handles 8-8 respectively fixed in their protruding ends, see Fig. 9.

The swing frame hase two relatively wide side bars 9-9 cross connected by the front and rear transverse bars 10-10, to form a rigid rectan ular frame, see Figs. 1-2. The pivot shaft passes through the ends of the side bars 9-9 which have the extensions 11'11 extending beneath the set screws 1212. These set screws are threaded in the brackets 1313 on the pillow bearings 3-3, see Figs. 8-9. By adjustin the screws 12-12 the plane of the swing rame when in operative position can be brought parallel 28. The retarding action due to the friction v height of the swing frame has been determined by adjusting the eccentrics 55.

The overhanging weight of the swing frame is counter-balanced by the counter weight 14 adjustable on the extension rods 1515 which are fixed in and extend rearwardly from the end bar 11, see Figs. 1---2.

The guide slots 1616 are milled in the inner faces of the side bars 9-9 to receive the crosshead guides 1717 on the opposite ends of the crosshead 18, extending across the width of the swing frame. The opposite! ends of the crosshead guides are split as at 19-19 so that they may be spread by the screws 20-20 so that they will exert a frictional resistance within the slots 1919, for reasons which will hereinafter appear.

The brackets 21-21 are a part of the crosshead guides and are slotted at 2222 to receive the opposite ends of the transverse ush rod 23 held therein by set screws. (See igs. 1011.)

The brackets 24-24 are fixed on the crosshead bar 18 by the setscrews 25--25. These brackets are cross-connected by the transverse fount pivot rod 28, passing through and fixed in the upward extensions 27-27 of the brackets. (See Figs. 2--12+--14.)

The ink fount comprises the rear plate 28 having the lugs 29-29 pivoted on the rod 26. This plate 28 is slotted in its lower edge to receive the spreader 30. The opposedplate 31 has the sides 32-32 engaging the edges of the plate 28 and also pivoted onthe rod 26. The lug 33 formed on the lower portion or any of the conventional coldr enamels used in screen printing. The sides 32-32 have the hooks 3535 formed thereon and engagin the push rod 23. (See Figs. 12-13.)

en the rod 23 is' pushed'forward, as shown in Fig. 12, the hooks 3535 push the plate 31 away from the plate 28 and open the fount at 36, perm tting the ink X to flow downward upon the screen stencil 37, across the surface of which it is spread by the spreader 30. The exact quantity of ink necessary to the re uired screen area isregulated by the ad uSting screw 38 threaded in the plate 31 and bearing against the plate between the spreader 30 against the screen 37 holds the plate 28 and transfers the thrustof the rod 23 to the plate 31, thus making the fount positive opening at 36.

C11 the reverse or back stroke the pull of the rod 23, engaging the hooks35-35, pulls the plate 31 against the plate 28, closing the opening at 36 and stopping the ink flow. This brings the plate 28 against the crosshead 18. The radius from the pivot 26 lifts the bearings 48-+48 fixed to the floor 1'. pinion 49 and the sprocket 50 are fixed on the countershaft 47. The rack 51 has teeth enthe stencil and scrapes any excess ink from the screen 37, to be redistribute'dfon the next stroke of thefount,

The slots 22-22 on the brackets i cause the push rod 23-to aactuate the-.-fount,i as described, before the -crosshead*18 moved. To insurefthis'synchrononsac 1s necessar to hold thefcrossheads up the 16stmotion rovidedfliin j the slots 22-22. ffThis'retardat on?isacc'omplished by spreading the slotted ends of the crossheads by means of the screws 2020. i

, The push rod 23 is actuated by the power.

mechanism as shown in Figs. l3567. Referring to Fig. 3, the motor 38vmounted on the floor 1 of the main frame, is belted at 39 to the shaft 40 of the reduction gear 41. The conventional motor R. P. M. of 1700 is reduced about to 1 in the reduction gear. Attention is directed to the fact that all the printing operations are actuated at relatively low speed, by thenovel combination of mechanical movements employed. The advantage of slow speed clutching, declutching, reciprocating and other movements is obvious.

The power from the reduction gear shaft 42 is transmitted through a clutch to the cam shaft. 43, journaled in the bearings 44-44 fixed to'the floor 1'. The cam 45 is fixed on this shaft between these hearings. (See Figs. 3-5.) This cam has the countour groove 46 formed in its face, which controls the raising and lowering of the swing frame and of the plate 31 is slotted to receive the spreader 34. The space between the latejs 28 and -31 forms a fount to hold the}; esir'd ink X the reciprocations of -the ink fount: V The countershaft 47 is journaled in the The meshed with the teeth of the pinion 49, and the head 52, slidable in the' guide 53 fixed to the floor l. The antifriction roller 54 is mounted on the side of the rack 51 and engages the contour groove 46 of the cam. The rack is reciprocatedby the rotation of the cam 45.

The reciprocation of therack oscillates the shaft 47, which is transmitted through the in the gui es 1-6-16', uritil thirod-23atakes sprocket chain 55,'to the s rocket 56' fixed on the shaft 57, which exten s across the width of the frame 1, and is suitably journaled in the bearings 58-58 mounted on the top rails 44 There are two pinions 59-59 fixed on the shaft 57, which are enmeshed with the racks 6060. The racks are guided in the saddles 61-61, pivoted on the shaft 57. (See Fig. 4.) These racks are joined at 62-62,-to the extensions 6363 which pivotally en age the opposite ends of the push rod 23. ee Figs. 110.

Through the drive mechanism just described the reciprocations of the rack 51 are transmitted to the racks -60 to push and pull the rod 23. In Fig. 1, the rod 23 has completed the forward stroke with the ink fount open is described and shown in Fig. 12. The 5 return stroke will close the fount as shown in Fig. 13. The completionof the return stroke will bring the cross head guides 17-17 to the ends of the guides 16-16 where they will stop, sothat the last portion of the pull of the rod 23 will swing the swing frame upward on its pivot 7 into the position indicated in dotted, lines in Fig. 1.

During the interval that the swing frame is up, the operator removes the printed impression sheet from the platen 2 and substitutes a blank sheet.

The first part. of the next forward thrust of the rod 23 will lower the swing frame to the platen, open the fount and push it forward across the stencil screen 37, asshown in Fig. 1, ready to repeat the operations .of'automatically printing through thescreen 37, as previously described. v

The clutch mechanism interposed": between the reduction gear 41 and the camshafte43, is best disclosed in Figsrl-3-6-7. Referring to Fig. 6, the disc 64'is fixed on-the end of the shaft 42. The clutch in's'65-65 are slidable in this disc and arehe' (1 extended by the springs 66-66 fixed to the rear face of the disc at 67 and have their freeends en-,

tered in holes through the pins -65.

splined on the end of the shaft 43 and is proed to re ister with the pins 65-65.

The c utch lever 71 is pivoted on the shaft 72 pivoted in the bearings 73-7 3, fixed on the floor 1. The upper end of the clutch lever is forked and slotted to receive the trunnions 75-75 on the yoke 76 engagiin the annular groove 77 in the hub 69. T tension of the clutch lever is in the form of an inverted Y to form the treadles 78-79, for the right and left feet of the operator respectively.

When the operator depresses the treadle 78 with his left foot, the dsc 68 slides back on its spline and d'sengages from the pins 65-65, disconnecting the prime mover from the printin mechanism. Contrawise vhen the treadle 79 is depressed the disc 68 approaches the disc 64, the ends of the spring pressed pins 65 riding the face of the disc 68 until they drop intothe holes 7 0, as shown in Fig. 6. It is important that the'power be declutched at a definite pointin the operation of the swing frame; for instance, when the swing frame is in the elevated position, see dotted lines in Fig.1. This is automatically accomplished by the trigger 80 pivoted on the shaft 72 with its inclined end 81 in the path of the V trip 82, fixed on the shaft 43. The machine is stopped by the operator removing both feet 65 from the treadles 78-79. The trip '82 then 'vided with the holes 70-70 which are adapt-' 8' ower EX- slides down the incline end 81 and forces the I trigger 80 outward against the tension of the spring 83 which pulls the clutch lever 71 with it and withdraws the disc 68 from engagement'with the clutch pins 65-65. This stops the swing frame in a position of its operation determined by the adjusted position of the trip 82. The treadle 78iisonly used in emergencies where it is desirable'to declutch regardless of other conditions;

The speed of the machine is to be timed with regard to the ability of a skilledoperator to feed it, without declutching-for each'cycle of operation. A skilled feeder will'fke'ep his foot on the treadle 79 for continuous operation, in which case the trip 82 will-merelysnap past the trigger 80, without declutchingfthe' power shaft 42. p

The platen 2 is inclined downward from th operator to facilitate the feeding operation.

The inclined platen has the further mechanical advantage that drivingthe spreader 30, up the incline, increases. its friction against the screen 37, the function ofwhich has been previously described. Pushing: the; ;flowing ink X against gravity also improves the uniformity of its-spread. The inclined platen I gives the operator a better view. of the printing field of the platen altholthe'arc of the v swing of the swing frame. is lessened several degrees, with its obvlousmechanlcal econom es and other advantages. a

The contour 46' of the cam' is plotted to initiate the raising and lowering operation of the swing frame at relatively slow speed, while thereciprocation of the'fount back and forth is speeded up. to the maximum that proper ink distribution will permit.

A multiplicityof founts can be strung upon the pivot rod 26, to simultaneously feed several colors ofinlrto the screen 37 if desired.

WVhenthe ink fount is removed, the screw 38 is turned until the opening 36 is clamped tight and the lugs 29-29 bear against the lugs 29-29' on t-he'sides 32-32, then the rod 26 is withdrawn laterally, and the hooks. 35-35 lifted arhqpushmd- 23.; When not in use the ink founts'willsta ndupright on the two spreaders30-34. r i i The frame 84 of the screen 37 is adjustab l 1' supported within the swing frame by the adr justing screws 85-85'fwhichare threaded i through the members' -gf-tl-lo-lo of" swing-frames The spreaders 30-34are preferably comof the Squeegees heretofore used in this art.

1-20, posed of leather andare set at about sixty degrees. to the plane of 'the screen 37 This angle gives a brushing or spreading effect as, di t nguished from-the harsh scraping action snreaders 30-34, forces the ink gently through the screen, with improvedtextural effects on the print rather, than to mash the screen down upon the impression surface and lift the ink as occurs with a heavily pressed squeegee as neretofore.

in addition to the counter wei ht 14, the swing frame is provided with'bu er springs, to cushion its rise and fall at the ends of the strokes of the reciprocating mechanism. Referring to Figs. 1-2, the collars 86-86 on the rods i5-1-5, anchor the transverse bar 87. A parallel transverse bar 88 is fixed across the main frame 1.

The sleeve 89 is pivoted on the bar 87 and has the stem 90.slidable through a hole in the bar 88. The adjustable collars 91-92 are fixed on the smm by the setscrews 93-94 rcspectiteiy. The expansion springs 9596 encircle the stem 90 between these adjustable collars and the bar 88.

Lowering the swing frame 9 compresses the spring 355, and raising the swing frame compresses spring 96. These springs thus resilicntlyfrrest the momentum of the swing frame, to prevent it banging'down onto the platen 2 and possibly breaking the brackets ll 11, on the down stroke-or rising too high on the up stroke.

Iifaving thus described thisinvention, what i claim and desire to secure" by Letters Patent is:

ii. A screen printing machine includinga main frame; a platen; a swing framepivoted on said main frame and adapted to carry a stencil above said platen; inking means guided on said swing frame; rack and inion means engaging said inking means a apted to raise and lower said serving frame; and a power driven cam means operatively engaging sa d rack and. pinion means.

2. A screen printing machine including a main frame; an inclined platen; a swing frame pivoted to said main frame and adapted to carry a stencil above said platen; inking means guided on said swing frame; a pinion on said main frame; a rack enmeshed with said pinion and pivoted to inking means and adapted to raise and lower said swing frame; and means for rotating said pinion.

3. A screen printing machine including a main frame; a platen; a swing frame pivoted to said main frame and adapted to carry a stencil above said platen; reciprocating means synchronously engaging said swing frame and inking means; and motor means geared to said reciprocating means.

i. A screen printing machine including a main frame; a platen; a swing frame pivoted to said main frame and adapted to carry a stencii above said platen; a crosshead guided in said swing frame; an inking means pivoted on said crosshead; a push rod engaging a slot in said crosshead and said inking means; reciprocating means engaging sald rod; and power m us for continuously operating said ed to said main frame and adapted to carr a stencil above said platen; a crosshead gui ed in said swing frame an inking means on said crosshead; reciprocating means engagin said crosshead for synchronously raising and lowering said swing frame, movin said crosshead and opening and closing said inking means on the forward and reverse strokes of said crosshead, respectively.

6. A screen printing machine including a main frame; a platen; a swing frame pivoted to said main/frame and adapted to carry a stencil above said platen; an inking means movable on said swing frame; reciprocating means for synchronously raising and lower- 'ing said swing frame, and movmg, opening and closing said inking means on the forward and reverse strokes of said reciprocating means;and a power operated means for actuating said reciprocating means.

7 A screen printing machine including a main frame; a platen; a screen frame movable on said main frame and adapted to carry a stencil above said platen; inking'means cooperating with said stencil; a power actuated cam on said main frame; a rack and pinion unit actuated by said cam; a second rack and pinion unit operatively engaging said inking means adapted to raise and lower said screen frame; and transmission means between said rack and pinion units.

8. A screen "printing machine including a main frame; a platen; a screen frame movable on said main frame and adapted to carry a stencil above said platen; inking means cooperating with said stencil; power operated means for automatically actuating said movable frame and inking means in synchronism; and clutch means adapted to apply the power at a predetermined point in the cycle of said automatic actuatin means.

9. A screen printing machine including a main frame; a platen; a screen frame movable with respect to said platen; inking means on said movable frame; power actuated shaft for automatically moving said movable frame and actuating said inking means in synchronism; and a clutch interposed in said shaft; a clutch operating lever; a trip on said shaft; a trigger in the path of said trip resiliently connected to said lever,

, said trip being set on said shaft with respect to'the operating cycle of said movable frame and inking means.

10. A screen printing machine including a main frame; a platen; a swing frame pivoted on said main frame and adapted to car ry a stencil above said platen; reciprocating means for raising and lowering said swing frame; and means between said main frame and swing frame adapted to be tensioned as said swing frame descends to resiliently arrest the movement of said swing frame.

11. A screen printing machine including a main frame; a platen mounted on said Ki) v to s}? 3 1,891,022 5 em a a frame; a swing frame pivoted to said main frame and adapted to carry a stencil above said laten; a crosshead having ides fric tiona ly slidable in said swing rame; ink- 5 ing means on said crosshead; reciprocating means engaging said crossheadfor raising and lowering said swing frame and sliding said crosshead. 12. A screen printing machine includin a main frame; a platen mounted on sai frame; a screen frame movable with respect to said platen; inking means on said movable frame; reciprocating means formoving said movable frame and actuating saidinking means; a prime mover for; dr vin'g'said reciprocating means a clutch interposed between said driving and reci rocatingmeans a lever for operating said '0 utch,peda ls connected to said operating lever for} engaging and disengaging said clutch, means-resilient ly connecte to said operating ilever; andjj adapted to disengage said clntch ,at apre-. determined point iintthe cycle; ofoperation of the mach ne a In testimony whereof Ihave hereunto set my hand this 5th da of December, 1930. J S FLOCKHART.